1. Field of the Invention
This invention relates to concrete strike-off vibrators and in particular, to a concrete strike-off vibrator having a pressurized fluid manifold communicating with the interiors of each of a plurality of cylinder assemblies disposed in a force-transmitting relationship within the manifold.
2. Description of the Prior Art
After a section of concrete has been layed, it is desirable to level the surface of that concrete to eliminate any undulations or discontinuities in the surface thereof. For this purpose the prior art utilizes a device known as a strike-off vibrator or a "crazy board". The strike-off vibrator is an elongated member having a flat strike-off surface thereon which is placed in contact with the upper surface of the concrete to be leveled. A plurality of fluid actuated piston-cylinder assemblies are mounted on the elongated strike-off member with each piston-cylinder assembly being provided with a separate pressurized fluid supply line.
A piston is disposed with each of the enclosed cylinders and moves within the cylinders in response to the introduction of pressurized fluid thereinto. The reaction forces generated by the collision of the piston member within the cylinder assemblies in response to the introduction of pressurized fluid is imparted to the elongated strike-off member and transmitted thereby to the concrete. The concrete responds to the vibratory motion of the stike-off member and undulations and discontinuities in the surface of the concrete are eliminated after passage of the strike-off vibrator thereover.
Current vibrators require, as discussed above, separate fluid inlet lines connecting a source of pressurized fluid, usually pressurized air, to each of the plurality of piston-cylinder assemblies disposed along the strike-off member. Such separate and independent fluid connections are disadvantageous, however, because of the unnecessary complexity of interconnections that is generated thereby. Furthermore, in practice it has been observed that individual ones of the fluid inlet lines have a tendency to separate themselves from their associated piston-cylinder assembly so that the introduction of pressurized fluid into that piston-cylinder assembly is terminated. Such an occurrence has the effect of reducing the vibratory motion and forces generated by the strike-off vibrator with a concommitant reduction in the efficiency of the leveling of the concrete.
It would be advantageous, therefore, to eliminate the heretofore complex fluid connection arrangements necessitated by the prior art. Accordingly, it is of advantage to provide a concrete strike-off vibrator utilizing a manifold member having an interior volume adapted to receive pressurized fluid thereinto. Furthermore, it is advantageous to provide a manifold adapted to receive a plurality of individual piston-cylinder assemblies therewithin in a force-transmitting relationship, each piston-cylinder assembly being interchangeably mounted and communicable with the interior of the manifold so that only a single pressurized fluid inlet is required to supply pressurized fluid to each piston-cylinder assembly associated with the strike-off.